Transistor for RF power amplifier with high linearity (OIP3 and OIP2)

[pavel_adameyko]

Hello, friends)
I need to choose transistor for power amplifier for application below 200 MHz. The main parameters are OIP3>+35 dBm and OIP2>+40 dBm, VCC≦5 V. Any suggestions?
Thanks for advance.

 

[tony_lth]

PHA-1+ from Mini-Circuits

 

[pavel_adameyko]

Thanks for your sharing)
But i can't find any information about IIP2 of PHA-1+ in their datasheet (**broken link removed** Have you worked with it and measure this parameter?

 

[tony_lth]

No, I seldom measured the OIP2.
Do you use the PHA-1 in mobile telecomm?
You can ask the Mini-Circuits for this data, or ask samples for test.

 

[ge]

>> OIP3>+35 dBm and OIP2>+40 dBm ?
Are you looking for an amplifier or transistor?
Have you considered a pair of BJTs in push pull? What do you consider "power amplifier". The BFG591 will easily do these IP.

 

[pavel_adameyko]

Actually what i want to construct is smth like medium power amplifier with output power 10-15 dBm. Bandwidth is a few MHz - 300 MHz.

 

[ge]

Everyone has a different definition of power amplifier. 10 - 15 dBm is relatively easy but making the OIP3 & "few MHz - 300 MHz" is a bit more tricky. There's many amplifier manufacturers out there that claim DC to GHz but they fall apart around 100MHz not DC. NXP makes some good devices as does Fairchild & OnSemi. I'm still thinking Push-Pull BJT using coax coupler.

 

[biff44]

use a switching regulator to get to 9V and use this:
TriQuint Semiconductor, Inc. - Product Information

 

[pavel_adameyko]

ECG008B from TriQuint Semiconductor, which you recommend, requires RF choke for biasing so how can i get, for example, 3-300 MHz bandwidth with inductive RF choke?

 

[biff44]

Use the bias network shown in the data sheet, with an inductor of around 680 nH. This one has an SRF of 530 MHz:


If you are not getting enough flatness at 3 MHz, try moving more of the shunt capacitance in the bias network to the other side of the series resistor.

 

[tony_lth]

I searched in web, and found this maybe you can use.
LQW2BHNR47K03 // 470 ±10% nH//160mA// 2.80 ohms max.// Q=15 //SRF= 350MHz min.// 0805